Noise-induced
hearing loss is the second most common occupational disease,
reducing the quality of life for millions of people who suffer
from it.

Loud machinery,
equipment or vehicles have always been considered the main culprits
for noise-induced hearing loss, but these are - to a great extent
- controlled by rules, regulations and careful monitoring.

For years it
was believed that being a call centre operator was a low-risk
occupation, but personal injury claims by call centre workers
are increasing. These include repetitive strain injury, eyesight
and posture problems, transient balance disorder, tinnitus and
noise-induced hearing loss.

One of the main
causes of hearing damage in a call centre is acoustic shock,
which occurs when a sudden and unexpected burst of high-frequency
noise is transmitted through the operators headset.

Dr Setsuo Maeda,
a Professor of Human Vibration at Kinki University, Osaka, Japan,
has conducted research to compare the use of conventional headsets
with bone-conducting devices - and to evaluate whether newly
available bone-conducting devices reduce the risk of temporary
or permanent hearing loss.

The testing took
six days, using a Head and Torso Simulator (HATS), supplied by
Brüel & Kjær. In parallel with the actual workers
making calls, the incoming call signal from the telephone was
divided between two headsets. A PULSE data acquisition system,
a monaural headset and a Personal Noise Dose Meter Type 4448
were also used.

The call
centre where we carried out the tests is small and noticeably
quieter than the large, international call centres that employ
hundreds of people, says Dr Maeda. In fact, the largest
call centre in Okinawa employs 3,000 people, making these workplaces
potentially much louder than the test call centre. My conclusion
is that hearing damage could occur at levels above 90 dB(A),
says Dr Maeda.

Dr Maeda has
also conducted laboratory experiments using HATS and PULSE to
compare normal headphones, with bone-conducting headsets, using
white noise and found: bone conducting devices help to
prevent hearing loss. This has also been confirmed by studies
carried out at the University of Southampton in the United Kingdom.

The full case
study is available on Brüel & Kjærs website:
www.bksv.com

About Bruel & KjaerBrüel
& Kjær is a world-leading manufacturer and supplier
of sound and vibration solutions for use in a wide range of applications
including environmental noise measurements, building acoustics,
vibration measurements and quality control for use in the automotive,
aerospace and consumer industries, as well as by local authorities.
Today Brüel & Kjær has 900 employees and sales
offices in 55 countries. Brüel & Kjær is a subsidiary
of UK-based Spectris plc. (www.spectris.com). Spectris has annual
sales of approximately £656m and employs around 6000 people
worldwide in its 15 business units.For more information, please contact
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